The invention relates to a security element with diffractions structures as set forth in the classifying portion of claim 1.
Such security elements comprise a thin layer composite of lacquer and/or plastic material, wherein embedded in the layer composite are at least relief structures from the group of diffraction structures, light-scattering structures and flat mirror surfaces. The security elements which are cut from the thin layer composite are glued onto articles for verifying the authenticity thereof.
The structure of the thin layer composite and the materials which can be used for that purpose are described for example in U.S. Pat. No. 4,856,857. It is known from DE 33 08 831 A1 for the thin layer composite to be applied to the article by means of a carrier film.
Security elements of that kind generally have a pattern of surface elements which are composed in a mosaic-like fashion and which are occupied by the microscopically fine relief structures. The pattern changes in a predetermined manner when the security element is tilted or rotated. Such a security element is known from EP 0 105 099 A1. So that the pattern can be easily recognized by an observer and, when the security element is tilted or rotated, appears as a striking, variable play of colors or iridescence effect, the microscopically fine relief structures of the surface elements have to deflect the light incident on the security element into the first few diffraction orders. The microscopically fine relief structures which satisfy that condition have structure elements which in principle can be copied with holographic means. Although the expenditure for producing a copy is high, there is nonetheless the need to be able to easily recognize counterfeit or copied patterns.